Modern computer-users generate a large amount of digital data every day in the form of digital files—including word processing documents, music files, digital spreadsheets, electronic pictures, among other types of well-known digital files. Accurately tracking the creation, revision, copying and transfer of digital files is a constant challenge for information technology professionals.
One of the qualities that information technology professionals often attempt to track is “custody” of a digital file—which can often described as the chronological documentation showing the seizure, custody, control, transfer and analysis and disposition or electronic evidence. In one sense, custody of a digital file is analogous to the ‘paper trail’ that is associated with a physical, paper file.
For example, custody of a digital file can be particularly important in modern legal proceedings where the process of electronic discovery is particularly concerned with how digital files have been stored, copied and otherwise manipulated.
Various prior art solutions have been proposed for tracking the chain of custody for a digital file. One such solution is using a digital “watermark” to inject identifying information into a digital file so that other systems that subsequently handle the digital file can examine this identifying information, thereby relating the document to a user and documenting a date and time when the document came into a particular user's possession.
However, it is not possible to watermark an object in a transient state, such as when the digital word document is displayed on a computer screen or when a music file is being played on a digital musical player. Further, many digital file formats do not support the ability to accept injected custom data from another source.
Another prior art solution involves associating additional metadata information (such as extended attributes or alternative data streams) to a digital file that includes specific information related to the chain of custody of the digital file. However, this approach has clear drawbacks as the additional metadata information is often not transferred along with the digital file when it is transferred over a network or moved to certain types of storage devices that do not support the additional metadata information.
Therefore, there is need for methods and file systems for accurately tracking the chain of custody between a source file and a destination file from a source file system to a destination file system.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.